/* -*- coding: utf-8 -*-
 *
 * 1947.cc:  No.1947 質より種類数 - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 5000;
const int MAX_V = 5000;

/* typedef */

typedef long long ll;

/* global variables */

ll dp[2][MAX_V + 1];

/* subroutines */

inline void setmax(ll &a, ll b) { if (a < b) a = b; }

/* main */

int main() {
  int n, v, c;
  scanf("%d%d%d", &n, &v, &c);

  fill(dp[0], dp[0] + v + 1, -1);
  dp[0][0] = 0;
  int cur = 0, nxt = 1;

  for (int i = 0; i < n; i++) {
    int vi, wi;
    scanf("%d%d", &vi, &wi);

    copy(dp[cur], dp[cur] + v + 1, dp[nxt]);

    int kv = vi, kw = c + wi;
    while (kv <= v) {
      int maxj = v - kv;
      for (int j = 0; j <= maxj; j++)
	if (dp[cur][j] >= 0)
	  setmax(dp[nxt][j + kv], dp[cur][j] + kw);
      kv += vi, kw += wi;
    }

    swap(cur, nxt);
  }

  ll maxd = 0;
  for (int j = 0; j <= v; j++) setmax(maxd, dp[cur][j]);

  printf("%lld\n", maxd);
  return 0;
}